I have trouble for 2 winters with my 4 WD not working. The first trip to the dealer they replaced my 4 WD switch. This did not fix the problem. I kept having to pull the famous #8 fuse and my 4 WD worked for a little while so I had the dealer replace the TCCM under the dash. I no longer have to pull #8 fuse. Now when I try to put the vehicle in 4WD the light blinks 15 times then it goes to a solid light then a minute later the service 4WD comes on and I am not in 4WD so I put it in to 2 wheel high but the solid light stays on the 4WD. Then every time I turn the vehicle off and back on I do not get a service 4WD light until I try to put it in 4WD or AWD. Any ideas? The selector switch has been changed. The transfer case control module has been changed. The oil in transfer case has been changed. And my 4WD drive still doesn't work. Any ideas?